Antibodies directed toward morphine, LSD, cannabis, normetanephrine, DMPE, DOM and mescaline have been produced in experimental animals and efforts are being continued to extend this list to other pharmacologically active substances and neurotransmitters. These antibodies will be characterized and used to estimate specific compounds of neruochemical interest in biological fluids and tissues. Radioimmunoassays will be developed to detect these compounds in picogram quantities. These antibodies will also be used to locate these compounds in the target cell. The ability of the antibodies to combine with and neutralize the effects of pharmacologically active substances may permit the neurochemist to use them as specific inhibitors in in vitro and in vivo experiments. A radioimmunoassay for indole (ethyl) amine N-methyltransferase enzymes will be developed based on the observation that the lysergamide antibody is sensitive to structural changes which occur when tryptamine and tryptamine derivatives are N-methylated. Since H3 LSD of high specific activity was found to bind strongly and specifically to the synaptic membranes of rat cortical gray matter, we are attempting to isolate the receptor site and study its interaction with LSD on the molecular level. The fact that LSD binding to synaptosomes is inhibited by 10 hallucinogenic compounds of widely varying structure but not by their non-hallucinogenic congeners, suggests that these compounds may produce their effects by binding to the same sites which bind LSD.